Iron is essential for life, so the body usually tightly controls iron absorption from food and recycles the iron from red blood cells. People lose small amounts of iron every day, and even a healthy diet contains only a small amount of iron. Thus, people rarely have too much iron in their body. Causes of excess iron in the body (iron overload) include the following:

When the body gradually takes in more iron than it needs, the excess iron is deposited in tissues throughout the body. Symptoms and complications can occur if iron accumulates in the endocrine organs (especially the pancreas, gonads, and pituitary gland), liver, and heart.

Taking in a large amount of iron all at once, such as in an overdose of iron pills, can be very dangerous. Iron poisoning damages the digestive tract, liver, heart and brain, and can be fatal.

If there is bleeding within an organ, such as in the lungs of people who have certain types of lung disease, iron from the blood cells often remains in that organ ( hemosiderosis). Depending on the amount of iron that remains in the lungs people may have no problems or varying degrees of lung damage.

If people have a disorder that causes excessive breakdown of red blood cells within the blood vessels (for example hemolytic anemia), iron released from the red blood cells can accumulate within the kidneys (renal hemosiderosis). Most cases of renal hemosiderosis do not cause kidney damage.

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